Circle-working implement



Feb. 2 1926.

- c. F. GOLDENV CIRCLE WORKING IMPLEMENT Filed April 24 1925 Patented Feb. 2, 1926.

UNITED STATES CHARLES FREMONT GOLDEN, OF DENVER, INDIANA.

CIRCLE-WORKING IMPLEMENT.

Application filed April 24, 1925. Serial No. 25,660.

To all whom it may concern:

Be it known that I, CHARLES FREMONT GOLDEN, a citizen of the United States, residing at Denver, in the county of Miami and State of Indiana, have invented a new and useful Circle-lVorking Implement, of which the following is a specification.

This invention relates to an implement primarily designed for making circles of desired diameter upon plain surfaces, such as a blackboard or the like, where it is ordinarily impossible to use the ordinary type of compass with certainty as to the result.

The object of the invention is to provide a simple and eflicient device of this character includin means for temporarily securing the center to the black-board without marring the same, and means whereby any desired radius may be readily obtained and maintained during operation.

The invention resides in the improvements in construction of the support or pivot members and of the means for holding the chalk which will be more readily understood from the following specification and claims.

In the accompanying drawings:

Figure 1 represents a top plan view of an implement constructed in accordance with this invention.

Fig. 2 is a side elevation thereof; and

Fig. 3 is a longitudinal section with the outer end of the beam broken off for convenience in illustration.

The invention is illustrated as applied to what is known as a beam compass in which 1 indicates the main rod or beam. This This beam 1 has a scale 2 reading from zero point adjacent the pivotal member 10 and having openings 3 coinciding with the unit graduations of the scale 2 and which are of sufiicient size to receive a piece of chalk.

The beam 1 carries at its inner end a hollow cup-shaped hub 4 having a laterally extending arm 5 at the flared mouth thereof which is screwed or otherwise suitably secured to the beam 1 and is equipped with openings 5 which register with the openings 2 in the beam as is shown clearly in Fig. 3. The hub .4; terminates in a reduced neck 6 wherein a plunger 7 is mounted for reciproplunger cation, said plunger being equipped, at its outer end with a button or knob 8, and at its inner end with a securing element 9 such as a headed screw and which operates to retain a resilient cup-shaped suction member 10 which is preferably constructed of rubber. A compression spring 11 surrounds the '7 one end of said spring engaging the knob 8 and the other end engaging the neck 6. said spring operating to normally force the plunger outward.

The hub i which is made of suitable metal surrounds a portion of the cup 10 and is designed to turn on the cup and the plunger. The head or screw 9 is embedded in the rubber from which cup 10 is formed.

The center of the suction member 10 and the center of knob 8 coincide with a line 12 drawn centrally through the beam 1, consequently-the button or knob 8 furnishes an 70 index whereby the suction cup 10 may be placed approximately at the desired point on the black-board. When it is so placed the plunger 7 is thrust inwardly by means of the knob 8, the spring 11 being compressed and the suction member 10 acquiring a hold on the black-board. hen so positioned the beam 1 is mounted on the black-board for swinging movement and has a piece of chalk placed in one of the openings 3, so that a circle or an arc of a circle may be struck.

Various changes in the form, shape, proportion and other minor details of construction may be made without departing from the principle or sacrificing any of the advantages of the claimed invention.

I claim 1. A device of the class described comprising a suction cup having a headed screw embedded in the apex thereof and extending outwardly, a post or plunger having thread ed engagement with said screw, a cup-shaped hub encompassing a portion of said cup and plunger, an arm extending radially from said hub, a beam fixedly secured to saidarm and 9 provided with a scale having a plurality of apertures registering with the graduations of said scale, and means for holding said hub frictionally engaged with said cup.

2. A device of the class described comprising a Suction cup, a plunger connected with the closed end thereof, a eupehapeil huh fitting over said cup and having a neck engaging saicl plunger, a knob on the outer end of the plunger, a spring between said knob and neck, said huh having an arm exlemling radially from one end, a beam arranged in lapping relation with said arm and fixedly secured thereh), said heam having a scale with apertures formed in the beam register 10 inn with Hie gqgrzulnatim'is of the scale.

In testimony that I claim The foregoing as my own, I have hereto ailllxed my signature.

CHARLES F. GOLDEN. 

